428 BULLETIN OF THE BUREAU OF FISHERIES. 



One of the largest genera of algae and one of the most difficult. There are few 

 sharply marked characters for distinguishing the species, it being mostly a question of 

 more or less in one respect or another. It is impossible for one not familiar with the 

 genus to determine the species without abundant authentic specimens for comparison. 



KEY TO SPECIES. 



0. Main filaments seldom reaching 150 mic. in diameter 6. 



b. Main filaments distinctly angled or flexuous i. C. flexuosa (p. 428). 



bb. Main filaments straight or nearly so 2. C. crystallina (p. 428). 



aa. Main filaments 150 mic. or more in diameter c. 



c. Lower cells less than 10 diameters long 3. C '. fascicularis (p. 428). 



cc. Lower cells 10 diameters long or more 4. C. prolifera (p. 429). 



1. Cladophora flexuosa (Mueller) Harvey. 



Conferva flexuosa, Mueller, in Flora Danica, torn. 5, pi. 882,^1782. 



Cladophora flexuosa, Harvey, 18493, p. 202. 



Cladophora flexuosa, Harvey, 1858, p. 78. 



Cladophora flexuosa, Farlow, 1882, p. 54. 



Cladophora flexuosa, De Toni, 1889, p. 311. 



Cladophora flexuosa, Collins, 1909, p. 339. 



A. A. B. Ex. No. 206. ' f 



P. B.-A. Nos. 1076, 1527, 2239. 



Fronds 10 to 20 cm. high, light green; main filaments 80 to 120 mic. diameter, regularly flexuous 

 with flexuous alternate branches, 40 to 80 mic. in diameter, with alternate or secund, curved, and some- 

 times refracted ramuli; cells from 6 diameters long below to 2 diameters in the ramuli. 



Newfoundland to Bermuda and Florida; Alaska; Europe. 



Abundant, attached and floating masses, Mullet Pond, Shackleford Banks, and fairly abundant 

 on rocks of Fort Macon jetties, Beaufort, N. C., about low-water line, April, 1908. 



This species closely approaches several others of the genus, but as none of these similar species has 

 been found at Beaufort, this fact need not give trouble there. Of the Beaufort species, it most nearly 

 resembles C. crystallina, from which it is distinguished by its flexuous, alternate branches. It has been 

 observed at Beaufort only in April, 1908, not being found there in May, 1907, and not being present in 

 Mullet Pond in August, 1907. 



2. Cladophora crystallina (Roth) Kuetzing. PI. LXXXIV, fig. i. 



Conferva crystallina. Roth, 1797, p. 196. 

 Cladophora crystallina, Kuetzing, 18453, p. 213. 

 Cladophora crystallina, De Toni, 1889, p. 318. 

 Cladophora crystallina, Collins, 1909, p. 342. 

 P. B.-A. Nos. 1581, 1865. 



Fronds yellowish or whitish green, soft, glossy, 10 to 30 cm. high; filaments slightly matted, dis- 

 tantly dichotomously or trichotomously branched; main branches 80 to 140 mic. in diameter, tapering to 

 25 to 40 mic. in the ramuli; branching erect or patent; upper ramuli sometimes whorled or alternately 

 secund; cells cylindrical, 4 to 12 diameters long. 



Massachusetts; West Indies; Bermuda; Europe. 



Abundant on sea buoy, Beaufort, N. C., July, 1907. 



A variable species, but usually marked by its light color and silky gloss. It is distinguished from 

 C. flexuosa, the Beaufort species which it most nearly resembles, by its dichotomous or trichotomous 

 branching and its straight branches. 



3. Cladophora fascicularis (Mertens) Kuetzing. 



Conferva fascicularis, Mertens, in Agardh, 1824, p. 114. 

 Cladophora fascicularis, Kuetzing, 1843, p. 268. 

 Cladophora fascicularis, De Toni, 1889, p. 316. 

 Cladophora fascicularis, Collins, 1909, p. 345. 

 P. B.-A. Nos. 122, 1228, 1472. 



